This is was one of those hikes that beat my expectation totally! I expected the hike to be a boring stroll (and, that is part of the reason, I didn't take it for such a long time), but it turned out to be a rather good workout, going all the way to the top of the face of the dam. The views were also spectacular, for the minimal amount of effort.
The trailhead is right before the Lake Poway entrance, on Espola Rd, in Rancho Bernardo.